In recent years, various flat-panel displays have been developed. Organic EL (electroluminescent) display devices, especially, are attracting much attention as excellent flat-panel displays, because these devices can achieve power saving, thickness reduction, increase in resolution, and the like.
In the field of such organic EL display devices, using a larger motherboard is more preferred in order to, for example, obtain a larger display screen and/or reduce production cost. In a case where a film is to be formed by vapor deposition on such a large motherboard having a large area, a vapor deposition source called a “line source” or a “linear source” is used. Such a vapor deposition source has nozzles via which a vapor deposition material is ejected in the form of vapor deposition particles, and these nozzles are arranged along one direction. Therefore, the vapor deposition source is generally longer in a first direction than in a second direction which is orthogonal to the first direction and in which the vapor deposition source or a board (substrate) is moved. A vapor deposition source for use in forming a film by vapor deposition on a large motherboard is hereinafter referred to as a line source.
(a) of FIG. 10 is a top view schematically illustrating a shape of a conventional line source, and (b) of FIG. 10 is a perspective view schematically illustrating the shape of the conventional line source.
In forming a film by vapor deposition on a large motherboard, it is very important to carry out the vapor deposition so that the resulting film will have a uniform thickness distribution. To this end, a line source 100 normally has a plurality of circular nozzles 101 via which a vapor deposition material is ejected in the form of vapor deposition particles (see (a) and (b) of FIG. 10).
The line source 100 is configured to be heated and thereby cause a vapor deposition material to be ejected in the form of vapor deposition particles outward through the circular nozzles 101. A method for heating and the like are not particularly limited. There is no particular limitation on a material for the line source 100, but the line source 100 is usually made from a material that is less prone to thermal shrinkage. The shape of the line source 100 is such that the line source 100 is longer in an X direction (shown in (a) and (b) of FIG. 10) than in a Y direction (shown in (a) and (b) of FIG. 10) that is orthogonal to the X direction.
The vapor deposition particles ejected from the circular nozzles 101 in an ejection face of the line source 100 are superposed on a substrate. This enables uniform vapor deposition over a large area.